Display screen or portion thereof with a transitional graphical user interface



The patent or application file contains at least one drawing executed in color. Copies of this patent or patent application publication with color drawing(s) will be provided by the Office upon request and payment of the necessary fee.

FIG. 1 is a front view of the first image of a display screen or portion thereof with a transitional graphical user interface showing the new design according to a first embodiment.

FIG. 2 is a front view of the second image thereof; and,

FIG. 3 is a front view of the third image thereof.

The appearance of the image transitions sequentially between the images shown in FIGS. 1-3. The process or period in which an image transitions to another forms no part of the claimed design. The broken line showing the display screen or a portion thereof, text, and graphic elements form no part of the claimed design. 

CLAIM The ornamental design for a display screen or portion thereof with a transitional graphical user interface, as shown and described. 